title: New pyrazolopyrimidine inhibitors of protein kinase d as potent anticancer agents for prostate cancer cells.
abstract: The emergence of protein kinase D (PKD) as a potential therapeutic target for several diseases including cancer has triggered the search for potent, selective, and cell-permeable small molecule inhibitors. In this study, we describe the identification, in vitro characterization, structure-activity analysis, and biological evaluation of a novel PKD inhibitory scaffold exemplified by 1-naphthyl PP1 (1-NA-PP1). 1-NA-PP1 and IKK-16 were identified as pan-PKD inhibitors in a small-scale targeted kinase inhibitor library assay. Both screening hits inhibited PKD isoforms at about 100 nM and were ATP-competitive inhibitors. Analysis of several related kinases indicated that 1-NA-PP1 was highly selective for PKD as compared to IKK-16. SAR analysis showed that 1-NA-PP1 was considerably more potent and showed distinct substituent effects at the pyrazolopyrimidine core. 1-NA-PP1 was cell-active, and potently blocked prostate cancer cell proliferation by inducing G2/M arrest. It also potently blocked the migration and invasion of prostate cancer cells, demonstrating promising anticancer activities on multiple fronts. Overexpression of PKD1 or PKD3 almost completely reversed the growth arrest and the inhibition of tumor cell invasion caused by 1-NA-PP1, indicating that its anti-proliferative and anti-invasive activities were mediated through the inhibition of PKD. Interestingly, a 12-fold increase in sensitivity to 1-NA-PP1 could be achieved by engineering a gatekeeper mutation in the active site of PKD1, suggesting that 1-NA-PP1 could be paired with the analog-sensitive PKD1(M659G) for dissecting PKD-specific functions and signaling pathways in various biological systems.
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Manuj
authors.initials: M
authors.lastname: Tandon
authors.forename: James
authors.initials: J
authors.lastname: Johnson
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Li
authors.forename: Shuping
authors.initials: S
authors.lastname: Xu
authors.forename: Peter
authors.initials: P
authors.lastname: Wipf
authors.forename: Qiming Jane
authors.initials: QJ
authors.lastname: Wang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; C089212:protein kinase D; D011493:Protein Kinase C; C030986:pyrimidine